Move over McDreamy, there’s a new hunk operating on Thursday nights, but he’s already a familiar face in primetime.

The sexy and lovable John Stamos has officially joined the cast of NBC’s long running medical drama, "ER," promoted from his recurring role as a Gulf War veteran.

"I think this is one of the first adult roles," John admitted. "I'm 43. It's time for me to start playing an adult man on television."

But the handsome doc told our A.J. Calloway the hardest part about his new gig is learning all those complicated medical terms.

"They shoot these long three and four-page scenes in one shot so everybody has their thing," John explained. "Andit's coming to the end of it, it’s coming to me, and your heart is starting to pound. Encephalitis…quitis!"

One thing John does not have trouble with, however, is living the single life since his divorce from Rebecca Romijn.

"I'm pretty much single," John admitted. "The first few years you flounder around, you run around or you try desperately to kind of replace your last relationship. Now I'm at a place where I'm happy dating, I’m happy staying at home. I stayed home last night and read a book."

Be sure to stay home each Thursday night to catch John’s latest chapter in the "ER."